# -*- coding: utf-8 -*-
import hashlib as hasher
import datetime as date

class Block:
	def __init__(self, index, timestamp, data, previous_hash):
		self.index = index
		self.timestamp = timestamp
		self.data = data
		self.previous_hash = previous_hash
		self.hash = self.hash_block()
	
	def hash_block(self):
		sha = hasher.sha256()
		tmp = str(self.index)+str(self.timestamp)+str(self.data)+str(self.previous_hash)
		sha.update(tmp.encode('utf-8'))
		return sha.hexdigest()

def create_genesis_block():
	#Manually construct a block with index zero and arbitrary hash 
	return Block(0, date.datetime.now(), "Genesis Block", "0")

def next_block(last_block):
	this_index = last_block.index+1
	this_timestamp = date.datetime.now()
	this_data = "hey I'am block "+str(this_index)
	this_hash = last_block.hash
	return Block(this_index, this_timestamp, this_data, this_hash)

#Create Block-chain and add the genesis block 
blockchain = [create_genesis_block()]
previous_block = blockchain[0]

#how many blocks we should add to the chain after the genesis block
num_of_blocks_to_add = 20

#Add blocks to the chain 
for i in range(0, num_of_blocks_to_add):
	block_to_add = next_block(previous_block)
	blockchain.append(block_to_add)
	previous_block = block_to_add

	#show them
	print("Block #{} has been add to the blockChain".format(block_to_add.index))
	print("Hash : {}\n".format(block_to_add.hash))




		
